Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 200612
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1040 PM PDT SUN OCT 19 2014

...AVIATION DISCUSSION UPDATED...

.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL BRING COOLER WEATHER THROUGH TUESDAY.
THERE WILL BE SOME LOCALLY GUSTY NORTHWEST WINDS LATE MONDAY THROUGH
TUESDAY NIGHT FOLLOWING THE PASSAGE OF THIS SYSTEM. A WARMING TREND
WILL BEGIN ON WEDNESDAY AS WEAK OFFSHORE FLOW DEVELOPS...WITH ABOVE
NORMAL TEMPERATURES EXPECTED LATER THIS WEEK. COOLER WEATHER LIKELY
RETURNS NEXT WEEKEND WITH THE NEXT LOW PRESSURE SYSTEM.

&&

.SHORT TERM (TONIGHT-WED)...
UPPER LEVEL TROUGH OF LOW PRESSURE OFF THE COAST OF NORTHERN AND
CENTRAL CALIFORNIA WILL CONTINUE TO TRACK EASTWARD AND PUSH THROUGH
THE REGION TOMORROW EVENING. IN ADVANCE OF THIS SYSTEM...MARINE LAYER
CLOUDS ARE EXPECTED TO INCREASE ACROSS MUCH OF THE AREA. CURRENT
SATELLITE IMAGERY ALREADY SHOWING A GOOD SURGE OF LOW CLOUDS
DEVELOPING ALONG THE CENTRAL COAST AS WELL AS PORTIONS OF THE
LA/VENTURA COUNTY COAST. THE MARINE LAYER DEPTH IS EXPECTED TO
INCREASE TO AROUND 2000 FEET OR GREATER OVERNIGHT INTO MONDAY
MORNING...WITH LOW CLOUDS AND FOG LIKELY SPREADING INTO MANY VALLEY
AREAS. ALSO...THERE COULD BE ENOUGH LIFT TO TRIGGER SOME PATCHY
DRIZZLE FOR AREAS NORTH OF POINT CONCEPTION.

SOME LOW LEVEL MOISTURE WILL LINGER INTO MONDAY AFTERNOON. THIS IN
COMBINATION WITH THE APPROACHING UPPER LEVEL TROUGH OF LOW PRESSURE
WILL LIKELY MAINTAIN A GOOD AMOUNT OF STRATOCUMULUS CLOUDS INTO THE
AFTERNOON HOURS. IN ADDITION...THERE WILL BE AN INFLUX OF MID AND
HIGH LEVEL CLOUDS WITH THIS SYSTEM ON MONDAY. MOST AREAS WILL SEE A
GOOD 3 TO 5 DEGREES OF COOLING ON MONDAY.

*** FROM PREVIOUS DISCUSSION ***

THE TROF MOVES OVERHEAD MONDAY NIGHT. THE COLD AIR AND THE MIXING
SHOULD WIPE OUT MOST OF THE INVERSION AND LOW CLOUDS WILL BE
CONFINED TO THE LONG BEACH AREA. GOOD NORTH FLOW SETS UP AS HIGH
PRESSURE BUILDS INTO CENTRAL VLY. LOOK FOR A DECENT SUNDOWNER...
SOME I-5 CORRIDOR WINDS AND THE LAKE CASITAS REGION. THE CENTRAL
COAST WILL SEE NE WINDS.

A BREEZY START TO THE DAY TUESDAY UNDER SUNNY SKIES SAVE FOR PERHAPS
THE LONG BEACH REGION. MAX TEMPS ARE THE REAL PROBLEM PART OF THE
FCST AS ALL THE COLD AIR BEHIND THE TROF WILL COMPETE WITH THE
OFFSHORE FLOW. THE INTERIOR WILL FOR SURE BE COOLER BUT THE CURRENT
COASTAL AND VLY FCST MAY BE SEVERAL DEGREES TOO COOL AND ACROSS THE
CENTRAL COAST AS MUCH AS 10 DEGREES TOO COOL. WILL TAKE A FURTHER
LOOK AT THIS WITH THE 00Z MDLS AND COULD WELL MAKE SOME UPWARD
ADJUSTMENTS.

LOOK FOR ANOTHER SUNDOWNER TUESDAY NIGHT. PERHAPS A LITTLE MORE
FOCUSED ON THE MONTECITO AREA. THERE COULD ALSO BE SOME MORE
NORTHEAST WINDS ACROSS THE CENTRAL COAST.

A BROAD RIDGE SETS UP OVER THE AREA WEDNESDAY. OFFSHORE FLOW REMAINS
BUT IT WILL BE MUCH WEAKER THAN ON TUESDAY. THERE WILL BE SOME 15 TO
20 MPH CANYON WINDS IN THE MOST SUSCEPTIBLE AREAS BUT THAT`S ABOUT
IT. THE LONG BEACH CATALINA AREA MAY HAVE SOME LOW CLOUDS SINCE THE
OFFSHORE FLOW DOES NOT AFFECT THAT AREA. HIGHER HGTS AND THE
OFFSHORE FLOW WILL ALLOW MOST AREAS TO WARM TO A LITTLE ABOVE NORMAL.

.LONG TERM (THU-SUN)...
MDLS AGREE THAT A 585 DM BROAD RIDGE ALONG WITH WEAK OFFSHORE WILL
DOMINATE THURSDAYS AND FRIDAYS WEATHER. THE OFFSHORE FLOW DOES NOT
LOOK TOO STRONG SO IT WILL MOSTLY SERVE TO WARM THINGS UP RATHER
THAN CREATE ANY DRAMATIC CANYON WINDS. MAX TEMPS ACROSS THE COASTS
AND VLYS WILL MOSTLY BE IN THE 80S WITH A SMATTERING OF 90S.

ALL OF THE MDLS AGREE THE RIDGE WILL BREAK DOWN OVER THE WEEKEND AND
IT WILL BE COOLER. THEY ALL DISAGREE ON WHETHER THE RIDGE WILL
MERELY SLIDE TO THE EAST OR IF A TROF WILL MOVE INTO CA. RIGHT NOW
PREFER THE EC SOLD OF SLIDING TO THE EAST SO WENT FOR A GRADUAL
COOLING TREND ALONG WITH A SLOW RETURN OF THE MARINE LAYER. IF THE
GFS VERIFIES THEN THE COOLING TREND WILL BE STRONGER AND THE MARINE
LAYER WILL BE MORE ROBUST.

&&

.AVIATION...20/06Z...

MARINE LAYER DEPTH AT KLAX AT 0515Z... 1800 FEET WITH A WEAK
INVERSION IN PLACE. INVERSION TOP IS AT 4100 FEET WITH A TEMPERATURE
OF 20 DEGREES C.

OVERALL...LOW TO MODERATE CONFIDENCE IN THE 06Z TAFS DUE TO
UNCERTAINTY WITH THE MARINE LAYER LOCATION... TIMING... AND
INTENSITY.  THE INVERSION ON THE KLAX SOUNDING REMAINS WEAK AND THE
INVERSION ON THE KVBG SOUNDING IS NOT MUCH STRONGER.  THESE ARE
BETTER CONDITIONS FOR A MARINE INTRUSION AT COASTAL AND ADJACENT
INLAND SITES THAN THEY WERE LAST NIGHT BUT STILL A CONCERN FOR
DEVELOPING AND KEEPING LOW CIGS IN THE TAFS.  A BIT MORE DEVELOPMENT
HAS ALREADY OCCURRED ALONG THE COAST SO WILL GO WITH IT AGAIN
TONIGHT BUT THERE IS A FORTY FIVE PERCENT CHANCE THAT THE CIGS WOULD
LIFT BY DAYBREAK AT ANY GIVEN LOCATION/S.  ANOTHER CHANCE AT A
MARINE INTRUSION AGAIN THE FOLLOWING NIGHT.  OTHERWISE AND
ELSEWHERE... VFR CONDITIONS WILL PREVAIL.

KLAX...LOW TO MODERATE CONFIDENCE IN THE 06Z TAF DUE TO UNCERTAINTY
WITH THE MARINE LAYER TIMING AND INTENSITY.  THE INVERSION ON THE
KLAX SOUNDING REMAINS WEAK AND THE INVERSION ON THE KVBG SOUNDING IS
NOT MUCH STRONGER.  THESE ARE BETTER CONDITIONS FOR A MARINE
INTRUSION THAN THEY WERE LAST NIGHT BUT STILL A CONCERN FOR
DEVELOPING AND KEEPING LOW CIGS IN THE TAF.  A BIT MORE DEVELOPMENT
HAS ALREADY OCCURRED ALONG THE COAST IN GENERAL SO WILL GO WITH IT
AGAIN TONIGHT BUT THERE IS A FORTY FIVE PERCENT CHANCE THAT THE CIGS
WOULD LIFT BY DAYBREAK.  ANOTHER CHANCE AT A MARINE INTRUSION AGAIN
THE FOLLOWING NIGHT.  OTHERWISE... VFR CONDITIONS WILL PREVAIL.

KBUR...LOW TO MODERATE CONFIDENCE IN THE 06Z TAF DUE TO UNCERTAINTY
WITH THE MARINE LAYER TIMING AND INTENSITY.  THE INVERSION ON THE
KLAX SOUNDING REMAINS WEAK AND THE INVERSION ON THE KVBG SOUNDING IS
NOT MUCH STRONGER.  THESE ARE BETTER CONDITIONS FOR A MARINE
INTRUSION THAN THEY WERE LAST NIGHT BUT STILL A CONCERN FOR
DEVELOPING AND KEEPING LOW CIGS IN THE TAF.  A BIT MORE DEVELOPMENT
HAS ALREADY OCCURRED ALONG THE COAST IN GENERAL SO WILL GO WITH IT
AGAIN TONIGHT BUT THERE IS A FORTY FIVE PERCENT CHANCE THAT ANY CIGS
THAT DEVELOP WOULD LIFT BY DAYBREAK.  ANOTHER CHANCE AT A MARINE
INTRUSION AGAIN THE FOLLOWING NIGHT.  OTHERWISE... VFR CONDITIONS
WILL PREVAIL.

&&

.MARINE...19/800 PM...

WIDESPREAD SMALL CRAFT ADVISORY WINDS EXPECTED BY MONDAY EVENING
ACROSS THE OUTER WATERS...WITH A CHANCE OF GALE FORCE WINDS. AS A
RESULT...A GALE WATCH HAS BEEN POSTED FOR THE OUTER WATERS. THERE IS
A CHANCE THAT THE GALES WILL PERSIST THROUGH LATE TUESDAY
NIGHT...WITH THE STRONGEST WINDS LIKELY FROM POINT SAL TO SAN
CLEMENTE ISLAND. SWELLS WITHIN 285-300 DEGREES RELATIVE TO THE LOS
ANGELES COUNTY COAST WILL BUILD MONDAY NIGHT THROUGH TUESDAY THEN
GRADUALLY SUBSIDE TUESDAY NIGHT THROUGH WEDNESDAY. THE LOCALLY
GENERATED SEAS AND DISTANT ARRIVING SWELLS WILL COMBINE AND CREATE
HAZARDOUS SEAS MONDAY THROUGH WEDNESDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY (SEE LAXCFWLOX).
GALE WATCH (SEE LAXMWWLOX).


&&
$$

PUBLIC...GOMBERG/RORKE
AVIATION...KJ
MARINE...GOMBERG/30
SYNOPSIS...SWEET

WWW.WEATHER.GOV/LOSANGELES






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